> -----Original Message-----
> From: Dave Reynolds [mailto:der@hplb.hpl.hp.com]
> Sent: Sunday, September 11, 2005 7:44 PM
> To: Giorgos Stamou
> Cc: 'Sandro Hawke'; public-rule-workshop-discuss@w3.org
> Subject: Re: Comments to Rules Working Group Charter Draft $Revision:
> 1.60$ (Part II)
>
> Giorgos Stamou wrote:
>
> > As I explained in my previous e-mail, it is much better to seriously
> > consider starting this work from the beginning, since it is very
> important
> > for this effort to follow all the phases of the work done within the WG.
>
> That's fair enough. I'm just concerned to limit the scope of the
> charter, where possible, to help the group complete its first round in
> reasonable time and to ensure that those features that are included are
> throughly examined by the whole working group.
[Giorgos Stamou]
OK, I just claimed that the reason that there is not enough manpower to work
on this now is not enough to leave this for the future.
>
> > I agree that the compatibility issue with RDF and OWL is very important
> and
> > I am looking forward to see how the new charter defines this
> compatibility.
> > In any case, a lot of work has been done in the area of fuzzy
> description
> > logics and could be used in the proposed effort. Some papers are cited
> in my
> > first e-mail from which you can find several references.
>
> I appreciate that much work has been done in the area. My question was
> whether that work was generally regarded as sufficiently complete. Is
> the overall community comfortable that the research issues have been
> resolved, that it is reasonably accepted that fuzzy logic is the
> appropriate uncertainty representation for the semantic web and that the
> time is ripe for standardization around that.
>
> That's a genuine question, not a rhetorical device.
>
> Is this a question we could pose to the Semantic Web Best Practices
> working group?
[Giorgos Stamou]
Well, I think this is a good idea. And since I am a member of the Semantic
Web Best Practices Working Group (also co-chairing a new Task Force on
Multimedia Annotation in the Semantic Web, an area that needs uncertainty
representation) I could certainly start this discussion there, as well.
The work on fuzzy logic has been started in 1965. And, in its late form (see
the book [Petr Hayek, Metamathematics of Fuzzy Logic, Kluwer Academic
Publishers 1998]), it is really a general framework covering several other
relevant theories of multi-valued logic. It is a clear and sound framework.
Still, it is not complete! But I think most theories in logics are not
"complete". I also think that the W3C Standardization process does not only
cover "complete" theories. Moreover, there is no final "agreement" of the
community that discusses the charter, in basic issues of classical logic
(consider the example of the usefulness of monotonic or non-monotonic
logic).
So, I understand your argument but I don't really think that we are very
confident with several other language extensions fairly included in the
charter. Moreover, obviously I did not propose uncertainty for the core
language. I only proposed to be included in the strongly-motivated in-scope
extensions to be considered.
>
> For good or ill, the emphasis of the draft charter is not on an
> implementable language but on an interlingua for exchange of rules
> between existing systems. It's not clear that the uncertainty use cases
> really fall into the interlingua remit. I would have thought that the
> issues of successful exchange and integration of rules involving
> uncertainty reasoning would be much greater that those of simply using
> fuzzy inference within a single system. Whereas the use cases seemed to
> want an implemented language they could use without a particular need
> for rule exchange.
[Giorgos Stamou]
I think they fall in the same framework. In the case you have different rule
systems dealing with uncertain and fuzzy rules, they should exchange these
rules in a similar form, in order to be able to deliver the uncertainty and
fuzziness.
>
> >> [der]
> >>Second, whilst I agree that fuzzy logic is well understood and is suited
> >>to
> >>use in rules, is it really so clear cut that it is the correct
> uncertainty
> >>representation to standardize? The use cases described at the workshop
> >>seemed be evidence combination problems that I would naively have
> expected
> >>to be as well suited to, say, a probabilistic approach.
> >
> >
> > [Giorgos Stamou]
> > The document I sent to Sandro leaves this issue quite open.
>
> The stated requirement to "generalize the two-valued Boolean logic of
> {0,1} into the interval [0,1]" seemed somewhat directed towards a fuzzy
> logic solution.
[Giorgos Stamou]
If it is because of the "[0,1]" requirement we could change it, although
fuzzy logic will also follow it (other relevant theories would not).
However, I think "[0,1]" is more preferable since it is a reasonable
extension of {0,1}.
>
> > We just need the industry requirements expressed in the Workshop and
> > strongly motivated the need for uncertainty and fuzziness, to be
> reflected
> > in the charter and hopefully this issue to be put with some few words in
> the
> > scope of the WG charter as a desired language extension.
>
> There are several industry requirements that are not reflected in the
> draft charter. I agree that this one is worthy of consideration but am
> less certain it is clear cut that it should included in the first round
> give the current emphasis on an interlingua.
>
> Dave
>
[Giorgos Stamou]
I understand that some language extensions will not be included and I
respect your opinion that there is no clear need for the uncertainty
extension to be included from the beginning (although if I correctly
understand you are positive to be included in the future). I also recognize
the very difficult and critical work of people writing the charter in order
to fairly balance it between several other people needs and wants.
But let me insist that it is fair enough to include the issue of
uncertainty, which was mentioned a lot by industrial participants in the
Workshop (which was organized mainly in order to find the industry
requirements), nobody is really against it, and does not change the work of
anybody.
Giorgos